Pore-suspending lipid bilayers on porous alumina investigated by electrical impedance spectroscopy
Pore-suspending lipid bilayers on porous alumina investigated by electrical impedance spectroscopy
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DOI：
10.1021/jp030762r
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发表时间：
2003-10-09
影响因子：
3.3
通讯作者：
Steinem, C
中科院分区：
文献类型：
--
作者：
Drexler, J;Steinem, C
孔径分别为 20 nm 和 50 nm 的无序和有序多孔氧化铝基材用于固定跨越多孔材料孔的脂质膜。通过干涉测量法和电阻抗光谱法对基底进行了表征。为了减少阻抗数据，在并联层模型的基础上开发了代表多孔氧化铝电学行为的等效电路。事实证明，所制备的氧化铝基材的电参数阻碍了对固定脂质膜形成的灵敏监测。因此，我们建立了一种技术来修改基材的电性能，从而显着增加多孔氧化铝的电容，从而可以通过阻抗光谱法灵敏地检测跨孔脂质双层。研究了两种基于囊泡铺展的不同膜制备技术。首先，在施加+100 mV的直流电压下将带负电的巨型脂质体铺展到多孔氧化铝表面上。其次，含有带有硫醇锚的脂质的大单层囊泡被用来化学吸附在金功能化多孔氧化铝基底上，随后破裂形成平面跨孔膜。对于这两种技术，都获得了阻抗谱，这表明在多孔氧化铝基材的顶部形成了脂质双层。
Nonordered and ordered porous alumina substrates with pore diameters of 20 and 50 nm, respectively, were utilized to immobilize lipid membranes spanning the pores of the porous material. The substrates were characterized by means of interferometry and electrical impedance spectroscopy. For impedance data reduction, an equivalent circuit representing the electrical behavior of porous alumina was developed on the basis of the parallel layer model. It turned out that the electrical parameters of the as prepared alumina substrates prevent a sensitive monitoring of the formation of immobilized lipid membranes. Thus, we established a technique to modify the substrates with respect to their electrical properties, leading to a significantly increased capacitance of porous alumina, which allowed for a sensitive detection of pore-spanning lipid bilayers by impedance spectroscopy. Two different membrane preparation techniques based on vesicle spreading were investigated. First, negatively charged giant liposomes were spread onto the porous alumina surface under an applied dc voltage of +100 mV. Second, large unilamellar vesicles containing lipids bearing a thiol anchor were used to chemisorb on gold functionalized porous alumina substrates and subsequently rupture to form planar pore-spanning membranes. For both techniques, impedance spectra were obtained, which indicate the formation of lipid bilayers on top of the porous alumina substrates.